In this question, we want to talk about many of Ayn Rand's novels in
the adjective
clause. So we have several things happening at once in this question. First,
we are are talking about Ayn Rand's,
not Ayn Rand. When we need to use the possessive form in an adjective
clause, we have to use whose. Next, we need to use a quantifier
to talk about a certain portion of the novels. The proper way to use quantifiers
is to use the quantifier
with of.